1. Field of the Invention
The present invention relates to polyvinyl ester macromonomers and their uses.
More specifically, the present invention relates to polyvinyl ester macromonomers usable as starting materials for graft polymers of which the composition, structure, molecular weight and the like are highly controlled, and to the uses thereof, i.e. polyvinyl alcohol macromonomers, polymers containing units from the polyvinyl ester macromonomers and polymers containing units from the polyvinyl alcohol macromonomers.
2. Description of the Prior Art
Macromonomers have been attracting much attention in recent years as starting materials for synthesizing highly controlled graft polymers and a large variety of macromonomers have been synthesized.
With respect to polyvinyl ester macromonomers, however, only a few synthesis examples have been reported. See for example Japanese Patent Application Laid-open No. 95215/1988 {hereinafter referred to as "Reference (A)"} for terminal-olefin macromonomers and J. Polymer Sci., Part C, Vol. 25, 175 (1987) {hereinafter referred to as "Reference (B)"} for terminal-styrene polyvinyl acetate macromonomers. These macromonomers have a drawback of low copolymerizability with other monomers, thereby hardly yielding polymers with high degree of polymerization. The polyvinyl acetate macromonomers described in Reference (B) have a drawback that their uses are significantly limited due to the presence of cationic groups in their linkage groups.
Also with respect to polyvinyl alcohol macromonomers, even including their precursors, only a few synthesis examples have been reported. For example hydrolysis of terminal-olefin polyvinyl acetate macromonomers (precursors) can give polyvinyl alcohol macromonomers {cf. Reference (A)}, which however have a drawback of low polymerizability and low copolymerizability with other monomers, thereby hardly yielding polymers with high degree of polymerization. There is known polyvinyl alcohol macromonomer obtained by hydrolyzing terminal-styrene polyvinyl acetate macromonomer (precursor) {cf. Reference (B)} and one obtained by hydrolyzing polydimethylaklylsylyl vinyl ether (precursor) {cf. Polymer Bulletin, 18, 473 (1987), hereinafter referred to as "Reference (C)"}. These macromonomers have low copolymerizability with other monomers due to steric hindrance produced by the terminal styrene, and the former macromonomer has a drawback that its uses are significantly limited due to the presence of cationic group in its linkage group part.
Japanese Patent Application Laid-open No. 89208/1986 {hereinafter referred to as "Reference (D)"} discloses polyvinyl alcohol macromonomers having at least 2 ester groups or amide groups at their linkage groups, which have drawbacks of low resistance to hydrolysis of the linkage groups and low polymerizability and copolymerizability with other monomers.
With respect to polymers containing units from polyvinyl ester macromonomers, which are obtained by polymerization of polyvinyl ester macromonomers, only those polymers that contain units from a terminal-styrene polyvinyl ester macromonomer are reported {cf. Reference (B)}. These polymers have low resistance to weather due to the presence of benzyl bonds in their linkage group parts, and hence their uses have, also from their linkage groups being of cationic nature, been significantly limited.
A number of examples have been reported for long with respect to branched polymers having polyvinyl alcohol as their branch and to branched polyvinyl alcohols, both of which present various interesting properties. However, on most of these polymers only the compositions are known, and it has thus been impossible with conventional process of polymerizing vinyl acetate in the presence of a trunk polymer and hydrolyzing the resulting graft polymer, to synthesize a polymer of which the composition, structure, molecular weight and the like are desirably controlled.
There have been reported in recent years the following polymers as polymers containing units from a polyvinyl alcohol macromonomer:
polymers containing units from a polyvinyl alcohol macromonomer, obtained by hydrolysis of polymers containing units from a terminal-styrene polyvinyl ester macromonomer {cf. Reference (B)},
polymers obtained by hydrolysis of terminal-styrene polydimethylalkylsilyl vinyl ether {cf. Reference (C)}, and
polymers containing units from a polyvinyl alcohol macromonomer that contains at least 2 ester groups or amide groups at its linkage group parts {cf. Reference (D)}.
These polymers, however, all have the following drawbacks:
The polymers disclosed in Reference (B) that contain units from a polyvinyl alcohol macromonomer have low weather resistance due to the presence of benzyl bonds at the linkage group parts originating in the polyvinyl alcohol macromonomer, and hence their uses will be, also from the cationic nature of their linkage groups, significantly limited. The polymers disclosed in Reference (C) that contain units from a polyvinyl alcohol macromonomer have low copolymerizability because of insufficient solubility of dimethylalkylsilyl vinyl ether that is the starting material for their synthesis in polymerization solvents, and hence their composition, structure and molecular weight cannot desirably be controlled. The polymers disclosed in Reference (D) that contain units from a polyvinyl alcohol macromonomer are low in the resistance to alkali of their linkage groups originating in the polyvinyl alcohol macromonomer.